What went wrong with the launch of ISRO’s earth watching satellite?

The Indian Space Research Organization’s (ISRO’s) plans to position a sophisticated Earth observation satellite (EOS-03) in space failed on Thursday, as GSLV-F10’s cryogenic upper stage ignition failed to kick in during a crucial phase.

What were the reasons for the failure?

An Indian GLSV rocket carrying the EOS-O3 Earth observation satellite for the Indian Space Research Organization lifts off from Second Launch Pad of the Satish Dhawan Space Centre on SriHarikota Island, India on Aug. 12, 2021. It failed to reach orbit. (Image credit: ISRO)

The launch took place from the second launch pad at the Satish Dhawan Space Centre, SriHarikota, at 05.43 am on 12 August. While the first two stages of the three-stage launch were successful, failure in the third stage prevented the successful placement of the satellite in orbit.

“GSLV-F10 launch took place today at 05:43 Hrs IST as scheduled. Performance of first and second stages was normal. However, cryogenic upper stage ignition did not happen due to technical anomaly. The mission couldn’t be accomplished as intended," ISRO tweeted.

As a result, the satellite failed to carry its payload to its destination.

What is a cryogenic stage in a launch?

Rockets require thrust to reach the desired location in space. Cryogenic engines use liquid oxygen and liquid hydrogen which propel rockets into orbit.

Cryogenic stage is considered a more efficient rocket launch method, providing more thrust for every kilogram of propellant burnt compared to solid and Earth-storable liquid propellant rocket stages.

Specific impulse achievable with cryogenic propellants is also much higher compared to Earth-storable liquid and solid propellants, giving it a substantial payload advantage. Two gimballed steering engines provide for control of the stage during its thrusting phase.

What was the objective of this space mission?

GSLV-F10 was to place EOS-03 in geostationary transfer orbit. The satellite was to be one of the country’s most sophisticated Earth imaging satellites. EOS-03 was to play a key role in providing real-time assistance and monitoring phenomena like floods, cyclones and other natural disasters, security threats, agriculture and forests cover.

Why is cryogenic stage so challenging?

Cryogenic stage is a very complex system because of its use of propellants at extremely low temperatures and the associated thermal and structural problems. For instance, oxygen liquifies at -183 degrees C and hydrogen at -253 degrees C. The propellants at these low temperatures are pumped using turbo pumps running at around 40,000 rpm. It also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, handling of cryo fluids, and related safety aspects.

What is next for the space agency?

This was ISRO’s first GSLV launch after the 2019 Chandrayaan-2 mission. The space agency had earlier in February successfully launched Brazil’s Amazonia-1 along with 18 co-passenger satellites using PSLV-C51. Much of the space projects though have been delayed due to the covid-19 pandemic.

However, ISRO is expected to launch some space projects in coming months, including the launch of EOS-04 sometime in the month of September. This will, however, be launched on a PSLV.

The last year has been a trying one for India's space program.

After the launch of EOS-01 in January 2020, the country's launches were placed on hold during the early days of the COVID-19 pandemic. The resumed late that year with two missions, one each in November and December. That November launch successfully placed the EOS-01 Earth observation satellite into orbit.

The delays from the pandemic prompted ISRO to move the launch of EOS-03 ahead of the EOS-02 mission, originally targeted to fly in March 2021, according to a report by the Indian Express news site. That mission had been rescheduled for no earlier than September and ISRO had planned to launch at least four more missions by the end of 2021, the report stated.

All five of those missions will likely be on hold as ISRO investigates the cause of the GSLV launch failure.